But Monsieur Nars is about to pull back the curtain with his new eponymous book called Francois Nars, out Sept. 6. It boasts 434 pages of vision boards, behind-the-scenes model Polaroids, fashion shoot outtakes, and even career advice. You can pre-order it on Amazon now, and keep reading for his candid thoughts on the beauty industry, the best celebrities to have in the makeup chair, and what he really thinks of YouTube tutorials.

Spoiler alert: He contours, too.

POPSUGAR: Mercury will be in retrograde when your book comes out. Are you worried? Do you believe in that stuff?

Francois Nars: Ehhh . . . I do and I don't. I do, yes, but you have to go through it. I mean I'm not going to stop doing jobs or cancel my travel plans just because the planets aren't aligned the right way. I know some people do change their lives around it — they'll decide not to travel or do any deals, but I'll never do that. Maybe that's why I've done some bad deals, who knows! [Laughing.]

PS: Do you pack more correcting products in your makeup kit during retrograde phases?

FN: Yeah, maybe more concealer. Maybe more makeup remover. Or maybe you just go with it and adopt a messier look. What are you going to do, other than go with the flow?

PS: But you don't always go with the flow! Your career took off because you were applying makeup with a very different technique, right?

FN: That's true. The very first time I went to a photo studio in Paris, they noticed me because I had a much lighter hand than other makeup artists. I used less product, and I think right away, in the industry at that time, [trends] went faster than ever. They looked at me and said, "My god, this guy is doing something different." I made the girl look fresher than what was going on at the time. I guess it was groundbreaking. It was definitely a rebellion.

I was very shy, but I believed in what I was doing.

PS: It's so funny to think of barely-there makeup as a rebellion.

FN: It's strange because I was so attracted by the very hard edge of ['80s] fashion photos. Those images pushed me to become a makeup artist. But when I finally became one, I went the opposite way than those photographs I loved so much growing up. The influence of my mom was very strong. She was not a Guy Bourdin kind of woman. She was more of a Hans Feurer woman — a little tan sometimes, glowing skin, but not really into sculpted, heavy makeup.

PS: Did her aesthetic make you want to change the makeup game?

FN: It did. I went that way first to make a statement in the fashion and makeup industry — that you don't need a mask of makeup. But my taste in the hard-edged images came back no matter what, so I started mixing. And I think that mix had a fresher approach. Even if I was doing a strong red lip, the skin would be lighter and more transparent. That made a big statement. Even when I was working with Irving Penn and [Richard] Avedon, my touch was lighter.

Nobody can tell you what to do or not do with makeup. So you have to trust your sixth sense about knowing what works.

PS: What made you brave enough to try something different, even when you were surrounded by the biggest legends in the business?

FN: The secret is if you believe in yourself. I was very shy, but I believed in what I was doing. You can be shy, you can be very discreet, but if you believe in what you do and the way you do it, then you have the guts and the balls to do it, and to follow through. Even if you're working with Richard Avedon, you know at the end that your work will stand out and look great. No matter what, it needs to look great. You can't break rules and then have the final look be bad! So you'd better be confident enough to know that if you break the rules, you're going to make it work. Otherwise, you're cooked.

PS: OK, but how do you know if your makeup works?

FN: The answer is, it's an instinct you have. It's something you either feel or don't feel. There isn't a written book, "this works, this doesn't work." I mean, there are books, but they're not true. Nobody can tell you what to do or not do with makeup. So you have to trust your sixth sense about knowing what works and doesn't work. At the end, you're the woman who should know what looks good on you.

PS: But your runway looks are sometimes so extreme. They aren't meant to look necessarily "good" on anyone.

FN: But the runway is the perfect lab to break rules. You can show the world different visions of beauty through a designer's clothes.

PS: Even if you can't wear it in real life?

FN:[Laughing] Makeup artists don't care about that! That's not important! Your runway, as a working woman, as a fun girl, as you, it can be anywhere you want. Your runway is real life. The runway, it's not about saying, "Is this possible for women?" Who gives a damn?! I don't care. I'm doing something first of all to please a designer. Are his clothes wearable by everybody? Probably not. Does he care? Definitely not . . . but when you do Marc's show, for example, the vision is not about pleasing people. We don't say, "Oh my god, is it possible for Madame to wear this makeup to the office?" That's not our purpose. We just do a vision that we have — like an artist painting something — and then hopefully there are always elements that you can grab in "real life."

PS: What do you think of YouTube? Do you think the video beauty tutorials are "real life"?

FN: Oh, it's outrageous. I think the tutorials are insane. Watching people apply contour is amazing. We used to do that to Naomi [Campbell] 20 years ago, but that was something that only professionals knew how to do. It's not easy. So when I watch YouTube, I always ask, "Is this person a makeup artist?" Because it's very hard to do. It can go wrong very easily. And some of them absolutely look like they know what they're doing.

PS: Wait, you think YouTubers really are beauty experts?

FN: I think they know how to create a look. But a lot of those looks are only for red carpet or for selfies. The makeup you see on the internet is so heavy! If you want to walk in the street like that, I mean . . . in daylight, it could look quite scary.

The freedom is what's big today. It would be very sad if everyone looked the same.

FN: Strobing? Are you serious? I love the name. Do they call it "hashtag strobing?" Okay. We've done that for 20 years or more — strobing, I mean, not hashtags. You just highlight your cheekbones. You know Marilyn Monroe used to do that herself, and she learned from her makeup artists. She put light on her chin you can always see it on camera. "Strobing," huh? Funny.

PS: Matte lips are having a moment. Can we declare them dead for Fall? Long live gloss?

FN: Oh, I like both of them. Matte, glossy, whatever. Some people look better glossy and some look better matte, especially red. And today everything is possible. There isn't just one fashion. The matte lipstick is big right now, and when it's red it looks like velvet. Beautiful. I don't think anyone should only wear one thing now, at least not for a long time. Even on TV, the girls have a matte lip, then a gloss. The freedom is what's big today. It would be very sad if everyone looked the same.

PS: You've worked with more celebrities than most Oscar winners. Who are your favorite actresses in the makeup chair?

FN: One is Tilda Swinton, always. And then I just worked with Sarah Paulson. I adore her. She can be definitely transformed into anything. I took some fantastic pictures of her. I mean, to die. You're going to love it when you see her. She's got one of those faces. That's why on American Horror Story she's so different each season. She's a fabulous actress and deserves so much more than what she gets. You know, and so many people in Hollywood get so much and they don't deserve it? She's the opposite. She is the next big star.

PS: Really?

FN: Sure. Until someone starts "strobing" on the internet, I guess. [Laughing.]